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  • richardmitnick 7:21 pm on October 16, 2018 Permalink | Reply
    Tags: , , , MIT, MIT Plasma Science and Fusion Center, Nuno Loureiro, Physicist explores the behavior of the universe’s most abundant form of matter, Physics of plasmas, Plasma is a sort of fourth phase of matter, The solar wind is the best plasma turbulence laboratory we have, Turbulence-a major stumbling block so far to practical fusion power   

    From MIT News-“Nuno Loureiro: Probing the world of plasmas” 

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    From MIT News

    October 15, 2018
    David L. Chandler

    A major motivation for moving to MIT from his research position, Nuno Loureiro says, was working with students. Image: Jared Charney

    Physicist explores the behavior of the universe’s most abundant form of matter.

    Growing up in the small city of Viseu in central Portugal, Nuno Loureiro knew he wanted to be a scientist, even in the early years of primary school when “everyone else wanted to be a policeman or a fireman,” he recalls. He can’t quite place the origin of that interest in science: He was 17 the first time he met a scientist, he says with an amused look.

    By the time Loureiro finished high school, his interest in science had crystallized, and “I realized that physics was what I liked best,” he says. During his undergraduate studies at the IST Lisbon, he began to focus on fusion, which “seemed like a very appealing field,” where major developments were likely during his lifetime, he says.

    Fusion, and specifically the physics of plasmas, has remained his primary research focus ever since, through graduate school, postdoc stints, and now in his research and teaching at MIT. He explains that plasma research “lives in two different worlds.” On the one hand, it involves astrophysics, dealing with the processes that happen in and around stars; on the other, it’s part of the quest to generate electricity that’s clean and virtually inexhaustible, through fusion reactors.

    Plasma is a sort of fourth phase of matter, similar to a gas but with the atoms stripped apart into a kind of soup of electrons and ions. It forms about 99 percent of the visible matter in the universe, including stars and the wispy tendrils of material spread between them. Among the trickiest challenges to understanding the behavior of plasmas is their turbulence, which can dissipate away energy from a reactor, and which proceeds in very complex and hard-to-predict ways — a major stumbling block so far to practical fusion power.

    While everyone is familiar with turbulence in fluids, from breaking waves to cream stirred into coffee, plasma turbulence can be quite different, Loureiro explains, because plasmas are riddled with magnetic and electric fields that push and pull them in dynamic ways. “A very noteworthy example is the solar wind,” he says, referring to the ongoing but highly variable stream of particles ejected by the sun and sweeping past Earth, sometimes producing auroras and affecting the electronics of communications satellites. Predicting the dynamics of such flows is a major goal of plasma research.

    “The solar wind is the best plasma turbulence laboratory we have,” Loureiro says. “It’s increasingly well-diagnosed, because we have these satellites up there. So we can use it to benchmark our theoretical understanding.”

    Loureiro began concentrating on plasma physics in graduate school at Imperial College London and continued this work as a postdoc at the Princeton Plasma Physics Laboratory and later the Culham Centre for Fusion Energy, the U.K.’s national fusion lab. Then, after a few years as a principal researcher at the University of Portugal, he joined the MIT faculty at the Plasma Science and Fusion Center in 2016 and earned tenure in 2017. A major motivation for moving to MIT from his research position, he says, was working with students. “I like to teach,” he says. Another was the “peerless intellectual caliber of the Plasma Science and Fusion Center at MIT.”

    Loureiro, who holds a joint appointment in MIT’s Department of Physics, is an expert on a fundamental plasma process called magnetic reconnection. One example of this process occurs in the sun’s corona, a glowing irregular ring that surrounds the disk of the sun and becomes visible from Earth during solar eclipses. The corona is populated by vast loops of magnetic fields, which buoyantly rise from the solar interior and protrude through the solar surface. Sometimes these magnetic fields become unstable and explosively reconfigure, unleashing a burst of energy as a solar flare. “That’s magnetic reconnection in action,” he says.

    Over the last couple of years at MIT, Loureiro published a series of papers with physicist Stanislav Boldyrev at the University of Wisconsin, in which they proposed a new analytical model to reconcile critical disparities between models of plasma turbulence and models of magnetic reconnection. It’s too early to say if the new model is correct, he says, but “our work prompted a reanalysis of solar wind data and also new numerical simulations. The results from these look very encouraging.”

    Their new model, if proven, shows that magnetic reconnection must play a crucial role in the dynamics of plasma turbulence over a significant range of spatial scales – an insight that Loureiro and Boldyrev claim would have profound implications.

    Loureiro says that a deep, detailed understanding of turbulence and reconnection in plasmas is essential for solving a variety of thorny problems in physics, including the way the sun’s corona gets heated, the properties of accretion disks around black holes, nuclear fusion, and more. And so he plugs away, to continue trying to unravel the complexities of plasma behavior. “These problems present beautiful intellectual challenges,” he muses. “That, in itself, makes the challenge worthwhile. But let’s also keep in mind that the practical implications of understanding plasma behavior are enormous.”

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  • richardmitnick 4:31 pm on October 16, 2018 Permalink | Reply
    Tags: Computer model offers more control over protein design, MIT   

    From MIT News: “Computer model offers more control over protein design” 

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    From MIT News

    October 15, 2018
    Anne Trafton

    Using a computer modeling approach that they developed, MIT biologists identified three different proteins that can bind selectively to each of three similar targets, all members of the Bcl-2 family of proteins. Image: Vincent Xue

    New approach generates a wider variety of protein sequences optimized to bind to drug targets.

    Designing synthetic proteins that can act as drugs for cancer or other diseases can be a tedious process: It generally involves creating a library of millions of proteins, then screening the library to find proteins that bind the correct target.

    MIT biologists have now come up with a more refined approach in which they use computer modeling to predict how different protein sequences will interact with the target. This strategy generates a larger number of candidates and also offers greater control over a variety of protein traits, says Amy Keating, a professor of biology and biological engineering and the leader of the research team.

    “Our method gives you a much bigger playing field where you can select solutions that are very different from one another and are going to have different strengths and liabilities,” she says. “Our hope is that we can provide a broader range of possible solutions to increase the throughput of those initial hits into useful, functional molecules.”

    In a paper appearing in the Proceedings of the National Academy of Sciences the week of Oct. 15, Keating and her colleagues used this approach to generate several peptides that can target different members of a protein family called Bcl-2, which help to drive cancer growth.

    Recent PhD recipients Justin Jenson and Vincent Xue are the lead authors of the paper. Other authors are postdoc Tirtha Mandal, former lab technician Lindsey Stretz, and former postdoc Lothar Reich.

    Modeling interactions

    Protein drugs, also called biopharmaceuticals, are a rapidly growing class of drugs that hold promise for treating a wide range of diseases. The usual method for identifying such drugs is to screen millions of proteins, either randomly chosen or selected by creating variants of protein sequences already shown to be promising candidates. This involves engineering viruses or yeast to produce each of the proteins, then exposing them to the target to see which ones bind the best.

    “That is the standard approach: Either completely randomly, or with some prior knowledge, design a library of proteins, and then go fishing in the library to pull out the most promising members,” Keating says.

    While that method works well, it usually produces proteins that are optimized for only a single trait: how well it binds to the target. It does not allow for any control over other features that could be useful, such as traits that contribute to a protein’s ability to get into cells or its tendency to provoke an immune response.

    “There’s no obvious way to do that kind of thing — specify a positively charged peptide, for example — using the brute force library screening,” Keating says.

    Another desirable feature is the ability to identify proteins that bind tightly to their target but not to similar targets, which helps to ensure that drugs do not have unintended side effects. The standard approach does allow researchers to do this, but the experiments become more cumbersome, Keating says.

    The new strategy involves first creating a computer model that can relate peptide sequences to their binding affinity for the target protein. To create this model, the researchers first chose about 10,000 peptides, each 23 amino acids in length and helical in structure, and tested their binding to three different members of the Bcl-2 family. They intentionally chose some sequences they already knew would bind well, plus others they knew would not, so the model could incorporate data about a range of binding abilities.

    From this set of data, the model can produce a “landscape” of how each peptide sequence interacts with each target. The researchers can then use the model to predict how other sequences will interact with the targets, and generate peptides that meet the desired criteria.

    Using this model, the researchers produced 36 peptides that were predicted to tightly bind one family member but not the other two. All of the candidates performed extremely well when the researchers tested them experimentally, so they tried a more difficult problem: identifying proteins that bind to two of the members but not the third. Many of these proteins were also successful.

    “This approach represents a shift from posing a very specific problem and then designing an experiment to solve it, to investing some work up front to generate this landscape of how sequence is related to function, capturing the landscape in a model, and then being able to explore it at will for multiple properties,” Keating says.

    Sagar Khare, an associate professor of chemistry and chemical biology at Rutgers University, says the new approach is impressive in its ability to discriminate between closely related protein targets.

    “Selectivity of drugs is critical for minimizing off-target effects, and often selectivity is very difficult to encode because there are so many similar-looking molecular competitors that will also bind the drug apart from the intended target. This work shows how to encode this selectivity in the design itself,” says Khare, who was not involved in the research. “Applications in the development of therapeutic peptides will almost certainly ensue.”

    Selective drugs

    Members of the Bcl-2 protein family play an important role in regulating programmed cell death. Dysregulation of these proteins can inhibit cell death, helping tumors to grow unchecked, so many drug companies have been working on developing drugs that target this protein family. For such drugs to be effective, it may be important for them to target just one of the proteins, because disrupting all of them could cause harmful side effects in healthy cells.

    “In many cases, cancer cells seem to be using just one or two members of the family to promote cell survival,” Keating says. “In general, it is acknowledged that having a panel of selective agents would be much better than a crude tool that just knocked them all out.”

    The researchers have filed for patents on the peptides they identified in this study, and they hope that they will be further tested as possible drugs. Keating’s lab is now working on applying this new modeling approach to other protein targets. This kind of modeling could be useful for not only developing potential drugs, but also generating proteins for use in agricultural or energy applications, she says.

    The research was funded by the National Institute of General Medical Sciences, National Science Foundation Graduate Fellowships, and the National Institutes of Health.

    See the full article here .

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  • richardmitnick 12:09 pm on October 15, 2018 Permalink | Reply
    Tags: An interdisciplinary hub for work in computer science AI data science and related fields, MIT, MIT Schwarzman College of Computing, Stephen A. Schwarzman   

    From MIT News: “MIT reshapes itself to shape the future” The MIT Stephen A. Schwarzman College of Computing 

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    From MIT News

    MIT will reshape itself to shape the future, investing $1 billion to address the rapid evolution of computing and AI — and its global effects. At the heart of this effort: a $350 million gift to found the MIT Stephen A. Schwarzman College of Computing. Photo: Christopher Harting

    Stephen Schwarzman. Photo courtesy of Blackstone

    October 15, 2018

    Kimberly Allen
    Email: allenkc@mit.edu
    Phone: 617-253-2702
    MIT News Office

    Gift of $350 million establishes the MIT Stephen A. Schwarzman College of Computing, an unprecedented, $1 billion commitment to world-changing breakthroughs and their ethical application.

    MIT today announced a new $1 billion commitment to address the global opportunities and challenges presented by the prevalence of computing and the rise of artificial intelligence (AI). The initiative marks the single largest investment in computing and AI by an American academic institution, and will help position the United States to lead the world in preparing for the rapid evolution of computing and AI.

    At the heart of this endeavor will be the new MIT Stephen A. Schwarzman College of Computing, made possible by a $350 million foundational gift from Mr. Schwarzman, the chairman, CEO and co-founder of Blackstone, a leading global asset manager.

    Headquartered in a signature new building on MIT’s campus, the new MIT Schwarzman College of Computing will be an interdisciplinary hub for work in computer science, AI, data science, and related fields. The College will:

    reorient MIT to bring the power of computing and AI to all fields of study at MIT, allowing the future of computing and AI to be shaped by insights from all other disciplines;
    create 50 new faculty positions that will be located both within the College and jointly with other departments across MIT — nearly doubling MIT’s academic capability in computing and AI;
    give MIT’s five schools a shared structure for collaborative education, research, and innovation in computing and AI;
    educate students in every discipline to responsibly use and develop AI and computing technologies to help make a better world; and
    transform education and research in public policy and ethical considerations relevant to computing and AI.

    With the MIT Schwarzman College of Computing’s founding, MIT seeks to strengthen its position as a key international player in the responsible and ethical evolution of technologies that are poised to fundamentally transform society. Amid a rapidly evolving geopolitical environment that is constantly being reshaped by technology, the College will have significant impact on our nation’s competitiveness and security.

    “As computing reshapes our world, MIT intends to help make sure it does so for the good of all,” says MIT President L. Rafael Reif. “In keeping with the scope of this challenge, we are reshaping MIT. The MIT Schwarzman College of Computing will constitute both a global center for computing research and education, and an intellectual foundry for powerful new AI tools. Just as important, the College will equip students and researchers in any discipline to use computing and AI to advance their disciplines and vice-versa, as well as to think critically about the human impact of their work. With uncommon insight and generosity, Mr. Schwarzman is enabling a bold agenda that will lead to a better world. I am deeply grateful for his commitment to our shared vision.”

    Stephen A. Schwarzman is chairman, CEO and co-founder of Blackstone, one of the world’s leading investment firms, with approximately $440 billion in assets under management. Mr. Schwarzman is an active philanthropist with a history of supporting education, culture, and the arts, among other things. Whether in business or philanthropy, he has dedicated himself to tackling global-scale problems, with transformative and paradigm-shifting solutions.

    This year, he gave $5 million to Harvard Business School to support the development of case studies and other programming that explore the implications of AI on industries and business. In 2015, Mr. Schwarzman donated $150 million to Yale University to establish the Schwarzman Center, a first-of-its-kind campus center in Yale’s historic Commons building. In 2013, he founded a highly selective international scholarship program, Schwarzman Scholars, at Tsinghua University in Beijing to educate future global leaders about China. At $578 million raised to date, the program is modeled on the Rhodes Scholarship and is the single largest philanthropic effort in China’s history coming largely from international donors.

    “There is no more important opportunity or challenge facing our nation than to responsibly harness the power of artificial intelligence so that we remain competitive globally and achieve breakthroughs that will improve our entire society,” Mr. Schwarzman says. “We face fundamental questions about how to ensure that technological advancements benefit all — especially those most vulnerable to the radical changes AI will inevitably bring to the nature of the workforce. MIT’s initiative will help America solve these challenges and continue to lead on computing and AI throughout the 21st century and beyond.”

    “As one of the world leaders in technological innovation, MIT has the right expertise and the right values to serve as the ‘true north’ of AI in pursuit of the answers we urgently need,” Mr. Schwarzman adds. “With the ability to bring together the best minds in AI research, development, and ethics, higher education is uniquely situated to be the incubator for solving these challenges in ways the private and public sectors cannot. Our hope is that this ambitious initiative serves as a clarion call to our government that massive financial investment in AI is necessary to ensure that America has a leading voice in shaping the future of these powerful and transformative technologies.”

    New college, structure, building, and faculty

    The MIT Schwarzman College of Computing represents the most significant structural change to MIT since the early 1950s, which saw the establishment of schools for management and for the humanities and social sciences:

    The College is slated to open in Sept. 2019, with construction of a new building for the College scheduled to be completed in 2022.
    Fifty new faculty positions will be created: 25 to be appointed to advance computing in the College, and 25 to be appointed jointly in the College and departments across MIT.
    A new deanship will be established for the College.

    Today’s news follows a period of consultation of the MIT faculty led by President Reif, Provost Martin Schmidt, and Dean of the School of Engineering Anantha Chandrakasan. The chair of the faculty, Professor Susan Silbey, also participated in these consultations. Reif and Schmidt have also received letters of support for the College from academic leadership across MIT.

    “Because the journey we embark on today will be Institute-wide, we needed input from across MIT in order to establish the right vision,” Schmidt says. “Our planning benefited greatly from the imagination of many members of our community — and we will seek a great deal more input over the next year. By design, the College will not be a silo: It will be connective tissue for the whole Institute.”

    “I see exciting possibilities in this new structure,” says Melissa Nobles, dean of the MIT School of Humanities, Arts, and Social Sciences. “Faculty in a range of departments have a great deal to gain from new kinds of algorithmic tools — and a great deal of insight to offer their makers. Faculty in every school at MIT will be able to shape the work of the College.”

    At its meeting on Oct. 5, the MIT Corporation — MIT’s board of trustees — endorsed the establishment of the College.

    Corporation Chair Robert Millard says, “The new College positions MIT to lead in this important area, for the benefit of the United States and the world at large. In making this historic gift, Mr. Schwarzman has not only joined a select group of MIT’s most generous supporters, he has also helped give shape to a vision that will propel MIT into the future. We are all deeply grateful.”

    Empowering the pursuit of MIT’s mission

    The MIT Schwarzman College of Computing will aspire to excellence in MIT’s three main areas of work: education, research, and innovation:

    The College will teach students the foundations of computing broadly and provide integrated curricula designed to satisfy the high level of interest in majors that cross computer science with other disciplines, and in learning how machine learning and data science can be applied to a variety of fields.
    It will seek to enable advances along the full spectrum of research — from fundamental, curiosity-driven inquiry to research on market-ready applications, in a wide range of MIT departments, labs, centers, and initiatives.

    “As MIT’s partner in shaping the future of AI, IBM is excited by this new initiative,” says Ginni Rometty IBM chairman, president, and CEO. “The establishment of the MIT Schwarzman College of Computing is an unprecedented investment in the promise of this technology. It will build powerfully on the pioneering research taking place through the MIT-IBM Watson AI Lab. Together, we will continue to unlock the massive potential of AI and explore its ethical and economic impacts on society.”

    Sparking thought around policy and ethics

    The MIT Schwarzman College of Computing will seek to be not only a center of advances in computing, but also a place for teaching and research on relevant policy and ethics to better ensure that the groundbreaking technologies of the future are responsibly implemented in support of the greater good. To advance these priorities, the College will:

    develop new curricula that will connect computer science and AI with other disciplines;
    host forums to engage national leaders from business, government, academia, and journalism to examine the anticipated outcomes of advances in AI and machine learning, and to shape policies around the ethics of AI;
    encourage scientists, engineers, and social scientists to collaborate on analysis of emerging technology, and on research that will serve industry, policymakers, and the broader research community; and
    offer selective undergraduate research opportunities, graduate fellowships in ethics and AI, a seed-grant program for faculty, and a fellowship program to attract distinguished individuals from other universities, government, industry, and journalism.

    “Computing is no longer the domain of the experts alone. It’s everywhere, and it needs to be understood and mastered by almost everyone. In that context, for a host of reasons, society is uneasy about technology — and at MIT, that’s a signal we must take very seriously,” President Reif says. “Technological advancements must go hand in hand with the development of ethical guidelines that anticipate the risks of such enormously powerful innovations. This is why we must make sure that the leaders we graduate offer the world not only technological wizardry but also human wisdom — the cultural, ethical, and historical consciousness to use technology for the common good.”

    “The College’s attention to ethics matters enormously to me, because we will never realize the full potential of these advancements unless they are guided by a shared understanding of their moral implications for society,” Mr. Schwarzman says. “Advances in computing — and in AI in particular — have increasing power to alter the fabric of society. But left unchecked, these technologies could ultimately hurt more people than they help. We need to do everything we can to ensure all Americans can share in AI’s development. Universities are best positioned for fostering an environment in which everyone can embrace — not fear — the transformations ahead.”

    In its pursuit of ethical questions, the College will bring together researchers in a wide range of MIT departments, labs, centers, and initiatives, such as the Department of Electrical Engineering and Computer Science; the Computer Science and Artificial Intelligence Lab; the Institute for Data, Systems, and Society; the Operations Research Center; the Quest for Intelligence, and beyond.

    “There is no doubt that artificial intelligence and automation will impact every facet of society. As we look to the future, we must utilize these important technologies to shape our world for the better and harness their power as a force for social good,” says Darren Walker, president of the Ford Foundation. “I believe that MIT’s groundbreaking initiative, particularly its commitment to address policy and ethics alongside technological advancements, will play a crucial role in ensuring that AI is developed responsibly and used to make our world more just.”

    Building on history and breadth

    The MIT Schwarzman College of Computing will build on MIT’s legacy of excellence in computation and the study of intelligence. In the 1950s, MIT Professor Marvin Minsky and others created the very idea of artificial intelligence:

    Today, Electrical Engineering and Computer Science (EECS) is by far the largest academic department at MIT. Forty percent of MIT’s most recent graduating class chose it, or a combination of it and another discipline, as their major. Its faculty boasts 10 of the 67 winners of the Turing Award, computing’s highest honor.

    The largest laboratory at MIT is the Computer Science and Artificial Intelligence Laboratory, which was established in 2003 but has its roots in two pioneering MIT labs: the Artificial Intelligence Lab, established in 1959 to conduct pioneering research across a range of applications, and the Laboratory for Computer Science, established in 1963 to pursue a Department of Defense project for the development of a computer system accessible to a large number of people.

    The College’s network function will rely on academic excellence across MIT. Outside of computer science and AI, the Institute hosts a high number of top-ranked departments, ready to be empowered by advances in these digital fields. U.S. News and World Report cites MIT as No. 1 in six graduate engineering specialties — and No. 1 in 17 disciplines and specialties outside of engineering, too, from biological sciences to economics.

    “A bold move to reshape the frontiers of computing is what you would expect from MIT,” says Eric Schmidt, former executive chairman of Alphabet and a visiting innovation fellow at MIT. “I’m especially excited about the MIT Schwarzman College of Computing, however, because it has such an obviously human agenda.” Schmidt also serves on the advisory boards of the MIT Quest for Intelligence and the MIT Work of the Future Task Force.

    “We count many MIT graduates among our team at Apple, and have long admired how the school and its alumni approach technology with humanity in mind. MIT’s decision to focus on computing and AI across the entire institution shows tremendous foresight that will drive students and the world toward a better future,” says Apple CEO Tim Cook.

    The path forward

    On top of Mr. Schwarzman’s gift, MIT has raised an additional $300 million in support, totaling $650 million of the $1 billion required for the College. Further fundraising is being actively pursued by MIT’s senior administration.

    Provost Schmidt has formed a committee to search for the College’s inaugural dean. He will also host forums in the coming days that will allow members of the MIT community to ask questions and offer suggestions about the College. The provost will work closely with the chair of the faculty and the dean of the School of Engineering to define the process for standing up the College.

    “I am truly excited by the work ahead,” Schmidt says. “The MIT community will give shape and energy to the College we launch today.”

    See the full article here .

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  • richardmitnick 10:03 am on October 15, 2018 Permalink | Reply
    Tags: Department of Mechanical Engineering, , MIT, Researchers quickly harvest 2-D materials bringing them closer to commercialization   

    From MIT News: “Researchers quickly harvest 2-D materials, bringing them closer to commercialization” 

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    From MIT News

    October 11, 2018
    Helen Knight

    Researchers in MIT’s Department of Mechanical Engineering have developed a technique to harvest 2-inch diameter wafers of 2-D material within just a few minutes. Image: Peng Lin

    Schematic illustration explaining the atomic scale manipulation of 2-D materials, in which thick wafer-scale 2-D materials are split into individual monolayers. Courtesy of the researchers.

    Efficient method for making single-atom-thick, wafer-scale materials opens up opportunities in flexible electronics.

    Since the 2003 discovery of the single-atom-thick carbon material known as graphene, there has been significant interest in other types of 2-D materials as well.

    These materials could be stacked together like Lego bricks to form a range of devices with different functions, including operating as semiconductors. In this way, they could be used to create ultra-thin, flexible, transparent and wearable electronic devices.

    However, separating a bulk crystal material into 2-D flakes for use in electronics has proven difficult to do on a commercial scale.

    The existing process, in which individual flakes are split off from the bulk crystals by repeatedly stamping the crystals onto an adhesive tape, is unreliable and time-consuming, requiring many hours to harvest enough material and form a device.

    Now researchers in the Department of Mechanical Engineering at MIT have developed a technique to harvest 2-inch diameter wafers of 2-D material within just a few minutes. They can then be stacked together to form an electronic device within an hour.

    The technique, which they describe in a paper published in the journal Science, could open up the possibility of commercializing electronic devices based on a variety of 2-D materials, according to Jeehwan Kim, an associate professor in the Department of Mechanical Engineering, who led the research.

    The paper’s co-first authors were Sanghoon Bae, who was involved in flexible device fabrication, and Jaewoo Shim, who worked on the stacking of the 2-D material monolayers. Both are postdocs in Kim’s group.

    The paper’s co-authors also included students and postdocs from within Kim’s group, as well as collaborators at Georgia Tech, the University of Texas, Yonsei University in South Korea, and the University of Virginia. Sang-Hoon Bae, Jaewoo Shim, Wei Kong, and Doyoon Lee in Kim’s research group equally contributed to this work.

    “We have shown that we can do monolayer-by-monolayer isolation of 2-D materials at the wafer scale,” Kim says. “Secondly, we have demonstrated a way to easily stack up these wafer-scale monolayers of 2-D material.”

    The researchers first grew a thick stack of 2-D material on top of a sapphire wafer. They then applied a 600-nanometer-thick nickel film to the top of the stack.

    Since 2-D materials adhere much more strongly to nickel than to sapphire, lifting off this film allowed the researchers to separate the entire stack from the wafer.

    What’s more, the adhesion between the nickel and the individual layers of 2-D material is also greater than that between each of the layers themselves.

    As a result, when a second nickel film was then added to the bottom of the stack, the researchers were able to peel off individual, single-atom thick monolayers of 2-D material.

    That is because peeling off the first nickel film generates cracks in the material that propagate right through to the bottom of the stack, Kim says.

    Once the first monolayer collected by the nickel film has been transferred to a substrate, the process can be repeated for each layer.

    “We use very simple mechanics, and by using this controlled crack propagation concept we are able to isolate monolayer 2-D material at the wafer scale,” he says.

    The universal technique can be used with a range of different 2-D materials, including hexagonal boron nitride, tungsten disulfide, and molybdenum disulfide.

    In this way it can be used to produce different types of monolayer 2-D materials, such as semiconductors, metals, and insulators, which can then be stacked together to form the 2-D heterostructures needed for an electronic device.

    “If you fabricate electronic and photonic devices using 2-D materials, the devices will be just a few monolayers thick,” Kim says. “They will be extremely flexible, and can be stamped on to anything,” he says.

    The process is fast and low-cost, making it suitable for commercial operations, he adds.

    The researchers have also demonstrated the technique by successfully fabricating arrays of field-effect transistors at the wafer scale, with a thickness of just a few atoms.

    “The work has a lot of potential to bring 2-D materials and their heterostructures towards real-world applications,” says Philip Kim, a professor of physics at Harvard University, who was not involved in the research.

    The researchers are now planning to apply the technique to develop a range of electronic devices, including a nonvolatile memory array and flexible devices that can be worn on the skin.

    They are also interested in applying the technique to develop devices for use in the “internet of things,” Kim says.

    “All you need to do is grow these thick 2-D materials, then isolate them in monolayers and stack them up. So it is extremely cheap — much cheaper than the existing semiconductor process. This means it will bring laboratory-level 2-D materials into manufacturing for commercialization,” Kim says.

    “That makes it perfect for IoT networks, because if you were to use conventional semiconductors for the sensing systems it would be expensive.”

    See the full article here .

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  • richardmitnick 9:33 am on October 10, 2018 Permalink | Reply
    Tags: , , MIT, , ,   

    From MIT: “A new path to solving a longstanding fusion challenge” 

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    From MIT News

    October 9, 2018
    David L. Chandler

    The ARC conceptual design for a compact, high magnetic field fusion power plant. The design now incorporates innovations from the newly published research to handle heat exhaust from the plasma. ARC rendering by Alexander Creely

    The ARC conceptual design for a compact, high magnetic field fusion power plant. Numbered components are as follows: 1. plasma; 2. The newly designed divertor; 3. copper trim coils; 4. High-temperature superconductor (HTS) poloidal field coils, used to shape the plasma in the divertor; 5. FLiBe blanket, a liquid material that collects heat from emitted neutrons; 6. HTS toroidal field coils, which shape the main plasma torus; 7. HTS central solenoid; 8. vacuum vessel; 9. FLiBe tank; 10. joints in toroidal field coils, which can be opened to allow for access to the interior. ARC rendering by Alexander Creely

    Novel design could help shed excess heat in next-generation fusion power plants.

    A class exercise at MIT, aided by industry researchers, has led to an innovative solution to one of the longstanding challenges facing the development of practical fusion power plants: how to get rid of excess heat that would cause structural damage to the plant.

    The new solution was made possible by an innovative approach to compact fusion reactors, using high-temperature superconducting magnets. This method formed the basis for a massive new research program launched this year at MIT and the creation of an independent startup company to develop the concept. The new design, unlike that of typical fusion plants, would make it possible to open the device’s internal chamber and replace critical comonents; this capability is essential for the newly proposed heat-draining mechanism.

    The new approach is detailed in a paper in the journal Fusion Engineering and Design, authored by Adam Kuang, a graduate student from that class, along with 14 other MIT students, engineers from Mitsubishi Electric Research Laboratories and Commonwealth Fusion Systems, and Professor Dennis Whyte, director of MIT’s Plasma Science and Fusion Center, who taught the class.

    In essence, Whyte explains, the shedding of heat from inside a fusion plant can be compared to the exhaust system in a car. In the new design, the “exhaust pipe” is much longer and wider than is possible in any of today’s fusion designs, making it much more effective at shedding the unwanted heat. But the engineering needed to make that possible required a great deal of complex analysis and the evaluation of many dozens of possible design alternatives.

    Taming fusion plasma

    Fusion harnesses the reaction that powers the sun itself, holding the promise of eventually producing clean, abundant electricity using a fuel derived from seawater — deuterium, a heavy form of hydrogen, and lithium — so the fuel supply is essentially limitless. But decades of research toward such power-producing plants have still not led to a device that produces as much power as it consumes, much less one that actually produces a net energy output.

    Earlier this year, however, MIT’s proposal for a new kind of fusion plant — along with several other innovative designs being explored by others — finally made the goal of practical fusion power seem within reach.

    MIT SPARC fusion reactor tokamak

    But several design challenges remain to be solved, including an effective way of shedding the internal heat from the super-hot, electrically charged material, called plasma, confined inside the device.

    Most of the energy produced inside a fusion reactor is emitted in the form of neutrons, which heat a material surrounding the fusing plasma, called a blanket. In a power-producing plant, that heated blanket would in turn be used to drive a generating turbine. But about 20 percent of the energy is produced in the form of heat in the plasma itself, which somehow must be dissipated to prevent it from melting the materials that form the chamber.

    No material is strong enough to withstand the heat of the plasma inside a fusion device, which reaches temperatures of millions of degrees, so the plasma is held in place by powerful magnets that prevent it from ever coming into direct contact with the interior walls of the donut-shaped fusion chamber. In typical fusion designs, a separate set of magnets is used to create a sort of side chamber to drain off excess heat, but these so-called divertors are insufficient for the high heat in the new, compact plant.

    One of the desirable features of the ARC design is that it would produce power in a much smaller device than would be required from a conventional reactor of the same output. But that means more power confined in a smaller space, and thus more heat to get rid of.

    “If we didn’t do anything about the heat exhaust, the mechanism would tear itself apart,” says Kuang, who is the lead author of the paper, describing the challenge the team addressed — and ultimately solved.

    Inside job

    In conventional fusion reactor designs, the secondary magnetic coils that create the divertor lie outside the primary ones, because there is simply no way to put these coils inside the solid primary coils. That means the secondary coils need to be large and powerful, to make their fields penetrate the chamber, and as a result they are not very precise in how they control the plasma shape.

    But the new MIT-originated design, known as ARC (for advanced, robust, and compact) features magnets built in sections so they can be removed for service. This makes it possible to access the entire interior and place the secondary magnets inside the main coils instead of outside. With this new arrangement, “just by moving them closer [to the plasma] they can be significantly reduced in size,” says Kuang.

    In the one-semester graduate class 22.63 (Principles of Fusion Engineering), students were divided into teams to address different aspects of the heat rejection challenge. Each team began by doing a thorough literature search to see what concepts had already been tried, then they brainstormed to come up with multiple concepts and gradually eliminated those that didn’t pan out. Those that had promise were subjected to detailed calculations and simulations, based, in part, on data from decades of research on research fusion devices such as MIT’s Alcator C-Mod, which was retired two years ago. C-Mod scientist Brian LaBombard also shared insights on new kinds of divertors, and two engineers from Mitsubishi worked with the team as well. Several of the students continued working on the project after the class ended, ultimately leading to the solution described in this new paper. The simulations demonstrated the effectiveness of the new design they settled on.

    “It was really exciting, what we discovered,” Whyte says. The result is divertors that are longer and larger, and that keep the plasma more precisely controlled. As a result, they can handle the expected intense heat loads.

    “You want to make the ‘exhaust pipe’ as large as possible,” Whyte says, explaining that the placement of the secondary magnets inside the primary ones makes that possible. “It’s really a revolution for a power plant design,” he says. Not only do the high-temperature superconductors used in the ARC design’s magnets enable a compact, high-powered power plant, he says, “but they also provide a lot of options” for optimizing the design in different ways — including, it turns out, this new divertor design.

    Going forward, now that the basic concept has been developed, there is plenty of room for further development and optimization, including the exact shape and placement of these secondary magnets, the team says. The researchers are working on further developing the details of the design.

    “This is opening up new paths in thinking about divertors and heat management in a fusion device,” Whyte says.

    “All of the ARC work has been both eye-opening and stimulating of new ways of looking at tokamak fusion reactors,” says Bruce Lipschultz, a professor of physics at the University of York, in the U.K., who was not involved in this work. This latest paper, he says, “incorporates new ideas in the field with the many other significant improvements in the tokamak concept. … The ARC study of the extended leg divertor concept shows that the application to a reactor is not impossible, as others have contended.”

    Lipschultz adds that this is “very high-quality research that shows a way forward for the tokamak reactor and stimulates new research elsewhere.”

    The team included MIT graduate students Norman Cao, Alexander Creely, Cody Dennett, Jake Hecla, Brian LaBombard, Roy Tinguely, Elizabeth Tolman, H. Hoffman, Maximillian Major, Juan Ruiz Ruiz, Daniel Brunner, and Brian Sorbom, and Mitsubishi Electric Research Laboratories engineers P. Grover and C. Laughman. The work was supported by MIT’s Department of Nuclear Science and Engineering, the Department of Energy, the National Science Foundation, and Mitsubishi Electric Research Laboratories.

    See the full article here .

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  • richardmitnick 9:05 pm on September 24, 2018 Permalink | Reply
    Tags: A big new home for the ultrasmall, MIT, The MIT.nano building   

    From MIT News: “A big new home for the ultrasmall” 

    MIT News
    MIT Widget

    From MIT News

    September 23, 2018
    David L. Chandler
    All images: Wilson Architects

    The MIT.nano building, at the center of campus adjacent to the Great Dome, has expansive glass facades that allow natural light into the labs while giving visitors a clear view of the research in action.

    The clean-room labs, occupying four interconnected floors of the building, will be available for use by researchers from any department and all five of MIT’s schools. The air purity is maintained by cycling the air through huge filtration systems.

    Occupying an entire additional floor over each of the clean-room floors, air handling and filtration systems exchange all the air in the labs 250 times an hour while they are in use.

    New, state-of-the-art chemistry teaching labs on the building’s top floor are already in use for fall-semester classes, and like most of MIT.nano’s spaces, feature broad windows that allow visitors to see the work going on inside.

    Nanotechnology, the cutting-edge research field that explores ultrasmall materials, organisms, and devices, has now been graced with the largest, most sophisticated, and most accessible university research facility of its kind in the U.S.: It is the new $400 million MIT.nano building, which will have its official opening ceremonies next week.

    The state-of-the-art facility includes two large floors of connected clean-room spaces that are open to view from the outside and available for use by an extraordinary number and variety of researchers across the Institute. It also features a whole floor of undergraduate chemistry teaching labs, and an ultrastable basement level dedicated to electron microscopes and other exquisitely sensitive imaging and measurement tools.

    “In recent decades, we have gained the ability to see into the nanoscale with breathtaking precision. This insight has led to the development of tools and instruments that allow us to design and manipulate matter like nature does, atom by atom and molecule by molecule,” says Vladimir Bulović, the Fariborz Maseeh Professor in Emerging Technology and founding director of MIT.nano. “MIT.nano has arrived on campus at the dawn of the Nano Age. In the decades ahead, its open-access facilities for nanoscience and nanoengineering will equip our community with instruments and processes that can further harness the power of nanotechnology in service to humanity’s greatest challenges.”

    “In terms of vibrations and electromagnetic noise, MIT.nano may be the quietest space on campus. But in a community where more than half of recently tenured faculty do work at the nanoscale, MIT.nano’s superb shared facilities guarantee that it will become a lively center of community and collaboration, says MIT President L. Rafael Reif. “I am grateful to the exceptional team — including Provost Martin Schmidt, Founding Director Vladimir Bulovic, and many others — that delivered this extraordinarily sophisticated building on an extraordinarily inaccessible construction site, making a better MIT so we can help to make a better world.”

    Accessible and flexible

    The 214,000-square-foot building, with its soaring glass facades, sophisticated design and instrumentation, and powerful air-exchange systems, lies at the heart of campus and just off the Infinite Corridor. It took shape during six years of design and construction, and was delivered exactly on schedule and on budget, a rare achievement for such a massive and technologically complex construction project.

    “MIT.nano is a game-changer for the MIT research enterprise,” says Vice President for Research Maria Zuber.

    “It will provide measurement, imaging, and fabrication capabilities that will dramatically advance science and technology in disciplines across the Institute,” adds Provost Martin Schmidt.

    At the heart of the building are two levels of clean rooms — research environments in which the air is continuously scrubbed and replaced to maintain a standard that allows no more than 100 particles of 0.5 microns or larger within a cubic foot of air. To achieve such cleanliness, work on the building has included strict filtration measures and access restrictions for more than a year, and at the moment, with the spaces not yet in full use, they far exceed that standard.

    All of the lab and instrumentation spaces in the building will be used as shared facilities, accessible to any MIT researcher who needs the specialized tools that will be installed there over the coming months and years. The tools will be continually upgraded, as the building is designed to be flexible and ready for the latest advances in equipment for making, studying, measuring, and manipulating nanoscale objects — things measured in billionths of a meter, whether they be technological, biological, or chemical.

    Many of the tools and instruments to be installed in MIT.nano are so costly and require so much support in services and operations that they would likely be out of reach for a single researcher or team. One of the instruments now installed and being calibrated in the basement imaging and metrology suites — sitting atop a 5-million-pound slab of concrete to provide the steadiest base possible — is a cryogenic transmission electron microscope. This multimillion dollar instrument is hosted in an equally costly room with fine-tuned control of temperature and humidity, specialized features to minimize the mechanical and electromagnetic interference, and a technical support team. The device, one of two currently being installed in MIT.nano, will enable detailed 3-D observations of cells or materials held at very low liquid-nitrogen temperatures, giving a glimpse into the exquisite nanoscale features of the soft-matter world.

    Almost half of the MIT.nano’s footage is devoted to lab space — 100,000 square feet of it — which is about 100 times larger in size than the typical private lab space of a young experimental research group at MIT, Bulović says. Private labs typically take a few years to build out, and once in place often house valuable equipment that is idle for at least part of the time. It will similarly take a few years to fully build out MIT.nano’s shared labs, but Bulović expects that the growing collection of advanced instruments will rarely be idle. The instrument sets will be selected and designed to drastically improve a researcher’s ability to hit the ground running with access to the best tools from the start, he says.

    Principal investigators often “find there’s a benefit to contributing tools to the community so they can be shared and perfected through their use,” Bulović says. “They recognize that as these tools are not needed for their own work 24/7, attracting additional instrument users can generate a revenue stream for the tool, which supports maintenance and future upgrades while also enhancing the research output of labs that would not have access to those tools otherwise.”

    A facility sized to meet demand

    Once MIT.nano is fully outfitted, over 2,000 MIT faculty and researchers are expected to use the new facilities every year, according to Bulović. Besides its clean-room floors, instrumentation floor, chemistry labs, and the top-floor prototyping labs, the new building also houses a unique facility at MIT: a two-story virtual-reality and visualization space called the Immersion Lab. It could be used by researchers studying subcellular-resolution images of biological tissues or complex computer simulations, or planetary scientists walking through a reproduced Martian surface looking for geologically interesting sites; it may even lend itself to artistic creations or performances, he says. “It’s a unique space. The beauty of it is it will connect to the huge datasets” coming from instruments such as the cryoelectron microscopes, or from simulations generated by artificial intelligence labs, or from other external datasets.

    The chemistry labs on the building’s fifth floor, which can accommodate a dozen classes of a dozen students each, are already fully outfitted and in full use for this fall. The labs allow undergraduate chemistry students an exceptionally full and up-to-date experience of lab processes and tools.

    “The Department of Chemistry is delighted to move into our new state-of-the-art Undergraduate Teaching Laboratories (UGTL) in MIT.nano,” says department head Timothy Jamison. “The synergy between our URIECA curriculum and this new space enables us to provide an even stronger educational foundation in experimental chemistry to our students. Vladimir Bulović and the MIT.nano team have been wonderful partners at all stages — throughout the design, construction, and move — and we look forward to other opportunities resulting from this collaboration and the presence of our UGTL in MIT.nano.”

    The building itself was designed to be far more open and accessible than any comparable clean-room facility in the world. Those outside the labs can watch through MIT.nano’s many windows and see the use of these specialized devices and how such labs work. Meanwhile, researchers themselves can more easily interact with each other and see the sunshine and the gently waving bamboo plants outdoors as a reminder of the outside world that they are working to benefit.

    A courtyard path on the south side of the building is named the Improbability Walk, in honor of the late MIT Institute Professor Emerita Mildred “Millie” Dresselhaus. The name is a nod to a statement by the beloved mentor, collaborator, teacher, and world-renowned pioneer in solid-state physics and nanoscale engineering, who once said, “My background is so improbable — that I’d be here from where I started.”

    Those who walk through the building’s sunlight-soaked corridors and galleries will notice walls surfaced with panels of limestone from the Yangtze Platform of southwestern China. The limestone’s delicate patterns of fine horizontal lines are made up of tiny microparticles, such as bits of ancient microorganisms, laid down at the bottom of primeval waters before dinosaurs roamed the Earth. The very newest marvels to emerge in nanotechnology will thus be coming into existence right within view of some of their most ancient minuscule precursors.

    See the full article here .

    Please help promote STEM in your local schools.

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    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

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  • richardmitnick 1:23 pm on September 23, 2018 Permalink | Reply
    Tags: , , , MIT, New battery gobbles up carbon dioxide,   

    From MIT News: “New battery gobbles up carbon dioxide” 

    MIT News
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    From MIT News

    September 21, 2018
    David L. Chandler

    This scanning electron microscope image shows the carbon cathode of a carbon-dioxide-based battery made by MIT researchers, after the battery was discharged. It shows the buildup of carbon compounds on the surface, composed of carbonate material that could be derived from power plant emissions, compared to the original pristine surface (inset). Courtesy of the researchers

    Scanning transmission electron microscope Wikipedia

    Lithium-based battery could make use of greenhouse gas before it ever gets into the atmosphere.

    A new type of battery developed by researchers at MIT could be made partly from carbon dioxide captured from power plants. Rather than attempting to convert carbon dioxide to specialized chemicals using metal catalysts, which is currently highly challenging, this battery could continuously convert carbon dioxide into a solid mineral carbonate as it discharges.

    While still based on early-stage research and far from commercial deployment, the new battery formulation could open up new avenues for tailoring electrochemical carbon dioxide conversion reactions, which may ultimately help reduce the emission of the greenhouse gas to the atmosphere.

    The battery is made from lithium metal, carbon, and an electrolyte that the researchers designed. The findings are described today in the journal Joule, in a paper by assistant professor of mechanical engineering Betar Gallant, doctoral student Aliza Khurram, and postdoc Mingfu He.

    Currently, power plants equipped with carbon capture systems generally use up to 30 percent of the electricity they generate just to power the capture, release, and storage of carbon dioxide. Anything that can reduce the cost of that capture process, or that can result in an end product that has value, could significantly change the economics of such systems, the researchers say.

    However, “carbon dioxide is not very reactive,” Gallant explains, so “trying to find new reaction pathways is important.” Generally, the only way to get carbon dioxide to exhibit significant activity under electrochemical conditions is with large energy inputs in the form of high voltages, which can be an expensive and inefficient process. Ideally, the gas would undergo reactions that produce something worthwhile, such as a useful chemical or a fuel. However, efforts at electrochemical conversion, usually conducted in water, remain hindered by high energy inputs and poor selectivity of the chemicals produced.

    Gallant and her co-workers, whose expertise has to do with nonaqueous (not water-based) electrochemical reactions such as those that underlie lithium-based batteries, looked into whether carbon-dioxide-capture chemistry could be put to use to make carbon-dioxide-loaded electrolytes — one of the three essential parts of a battery — where the captured gas could then be used during the discharge of the battery to provide a power output.

    This approach is different from releasing the carbon dioxide back to the gas phase for long-term storage, as is now used in carbon capture and sequestration, or CCS. That field generally looks at ways of capturing carbon dioxide from a power plant through a chemical absorption process and then either storing it in underground formations or chemically altering it into a fuel or a chemical feedstock.

    Instead, this team developed a new approach that could potentially be used right in the power plant waste stream to make material for one of the main components of a battery.

    While interest has grown recently in the development of lithium-carbon-dioxide batteries, which use the gas as a reactant during discharge, the low reactivity of carbon dioxide has typically required the use of metal catalysts. Not only are these expensive, but their function remains poorly understood, and reactions are difficult to control.

    By incorporating the gas in a liquid state, however, Gallant and her co-workers found a way to achieve electrochemical carbon dioxide conversion using only a carbon electrode. The key is to preactivate the carbon dioxide by incorporating it into an amine solution.

    “What we’ve shown for the first time is that this technique activates the carbon dioxide for more facile electrochemistry,” Gallant says. “These two chemistries — aqueous amines and nonaqueous battery electrolytes — are not normally used together, but we found that their combination imparts new and interesting behaviors that can increase the discharge voltage and allow for sustained conversion of carbon dioxide.”

    They showed through a series of experiments that this approach does work, and can produce a lithium-carbon dioxide battery with voltage and capacity that are competitive with that of state-of-the-art lithium-gas batteries. Moreover, the amine acts as a molecular promoter that is not consumed in the reaction.

    The key was developing the right electrolyte system, Khurram explains. In this initial proof-of-concept study, they decided to use a nonaqueous electrolyte because it would limit the available reaction pathways and therefore make it easier to characterize the reaction and determine its viability. The amine material they chose is currently used for CCS applications, but had not previously been applied to batteries.

    This early system has not yet been optimized and will require further development, the researchers say. For one thing, the cycle life of the battery is limited to 10 charge-discharge cycles, so more research is needed to improve rechargeability and prevent degradation of the cell components. “Lithium-carbon dioxide batteries are years away” as a viable product, Gallant says, as this research covers just one of several needed advances to make them practical.

    But the concept offers great potential, according to Gallant. Carbon capture is widely considered essential to meeting worldwide goals for reducing greenhouse gas emissions, but there are not yet proven, long-term ways of disposing of or using all the resulting carbon dioxide. Underground geological disposal is still the leading contender, but this approach remains somewhat unproven and may be limited in how much it can accommodate. It also requires extra energy for drilling and pumping.

    The researchers are also investigating the possibility of developing a continuous-operation version of the process, which would use a steady stream of carbon dioxide under pressure with the amine material, rather than a preloaded supply the material, thus allowing it to deliver a steady power output as long as the battery is supplied with carbon dioxide. Ultimately, they hope to make this into an integrated system that will carry out both the capture of carbon dioxide from a power plant’s emissions stream, and its conversion into an electrochemical material that could then be used in batteries. “It’s one way to sequester it as a useful product,” Gallant says.

    “It was interesting that Gallant and co-workers cleverly combined the prior knowledge from two different areas, metal-gas battery electrochemistry and carbon-dioxide capture chemistry, and succeeded in increasing both the energy density of the battery and the efficiency of the carbon-dioxide capture,” says Kisuk Kang, a professor at Seoul National University in South Korea, who was not associated with this research.

    “Even though more precise understanding of the product formation from carbon dioxide may be needed in the future, this kind of interdisciplinary approach is very exciting and often offers unexpected results, as the authors elegantly demonstrated here,” Kang adds.

    See the full article here .

    Please help promote STEM in your local schools.

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    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

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  • richardmitnick 3:25 pm on September 19, 2018 Permalink | Reply
    Tags: "Dispatches from Planet 3", Book explores milestones of astronomical discovery, Marcia Bartusiak, MIT,   

    From MIT News: Women in STEM- “Book explores milestones of astronomical discovery” Marcia Bartusiak 

    MIT News
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    From MIT News

    September 18, 2018
    Peter Dizikes

    Marcia Bartusiak and her new book, Dispatches from Planet 3

    In Dispatches from Planet 3, Marcia Bartusiak illuminates overlooked breakthroughs and the people who made them.

    Here’s quick rule of thumb about the universe: Everything old is new again.

    Those materials being used when new stars or planets form are just recycled cosmic matter, after all. But also, even our latest scientific discoveries may not be as new as they seem.

    That’s one insight from Marcia Bartusiak’s new book, “Dispatches from Planet 3,” published by Yale University Press, a tour of major discoveries in astronomy and astrophysics that digs into the history behind these breakthroughs.

    “No discovery comes out of the blue,” says Bartusiak, professor of the practice in MIT’s Graduate Program in Science Writing. “Sometimes it takes decades of preparation for [discoveries] to be built, one brick at a time.”

    The book, drawn from her columns in Natural History, underscores that point by highlighting unheralded scientists whose work influenced later discoveries.

    Moreover, as Bartusiak observes in the book, recent scientific debates often echo older arguments. Take the kerfuffle last decade about whether or not Pluto should be regarded as a proper planet in our solar system. As Bartusiak recounts in the book, the same thing happened multiple times in the 19th century, when objects called Ceres, Vesta, and Juno first gained and then lost membership in the club of planets.

    “Ceres in the 19th century was a certified planet, along with Vesta and Juno, the big asteroids, until they got demoted into the general asteroid belt,” Bartusiak says. “Then the same thing happened again, and everyone said, ‘Poor Pluto, it’s not a planet any more.’ Well, I’m sure in the 19th century there were people going ‘Poor Ceres, it’s not a planet.’ We’ll get over it.”

    (Demoting Pluto, by the way, is a judgment Bartusiak is comfortable with: “They made the right decision. Pluto is a dwarf planet. It’s part of the Kuiper Belt. I’m sure I’ll get a lot of people mad with me, [but] it makes sense to have Pluto in that group, rather than … with the big terrestrial planets and the gas giants.” [There is a move afoot to restore Pluto as a planet. In a study of over 1000 documents only one required that to be a planet the body must clear out is orbit, and that is the thing that got Pluto kicked out.])

    One astronomer who made a crucial Pluto-related discovery was Jane X. Luu, who helped locate asteroids orbiting the sun from even farther away. Luu is just one of many women in “Dispatches from Planet 3” — although, Bartusiak says, that was not by design, but simply a consequence of hunting for the origins of important advances.

    “I did not have an agenda for this book,” Bartusiak says. “I have always been the type of writer that wanted to follow my nose on what the most interesting findings, discoveries, and theories were, without worrying about who was doing them.”

    But as it happens, many stories about the development of scientific knowledge involve accomplished female scientists who did not immediately become household names.

    Consider the astronomer Cecilia Payne-Gaposchkin, who in the 1920s, Bartusiak notes, “first knew that hydrogen is the major element of the universe. A major discovery! This is the fuel for stars. It was central to astronomical studies. And yet, the greatest astronomer of the time, Henry Norris Russell, made her take [the idea] out of her thesis before they would accept it at Harvard.”

    Bartusiak’s book also recounts the career of Beatrice Tinsley, an astrophysicist who in the 1970s developed important work about the ways galaxies change over time, before she died in her early 40s.

    “Who really started thinking about galaxy evolution?” Bartusiak asks. “Beatrice Tinsley, ignored when she first started doing this, [produced] one of the most accomplished PhD theses in astronomical history. She was the first to really take it seriously.”

    The notion that galaxies evolve, Bartusiak’s book reminds us, is a relatively recent concept, running counter to ages of conventional wisdom.

    “People thought of the universe as being serene [and that] every galaxy was like the Milky Way,” Bartusiak says. “And that was based on what they could see.” Deep in the postwar era, our empirical knowledge expanded, and so did our conception of galactic-scale activity.

    In fairness, the Milky Way is pretty placid at the moment.

    Milky Way NASA/JPL-Caltech /ESO R. Hurt

    “It will get active again when we collide with Andromeda, 4 billion years from now,” Bartusiak says.

    Andromeda Galaxy NASA/ESA Hubble

    NAOJ Milky Way merger with Andromeda

    “We’re lucky we’re not in the galactic center or in a very active star cluster [I think this is off.Even in a “crowded gluster stars are millions of miles apart.]. You have stars blowing up, and it probably would be hard for life to start if you were in an area where X-rays were raining down on you, or if a supernova was going off nearby. We’re off in a little spur in a very quiet part of the Milky Way galaxy, which has enabled life on Earth here to evolve and flourish without a cosmic incident raining havoc down upon us.”

    Bartusiak closes the book with chapters on black holes, the idea of the multiverse, and our problems in conceptualizing what it means to think that the universe had a beginning.

    “We think that black holes and gravitational waves are strange, but there may stranger things to come,” Barytusiak says. “As I say in a chapter with [Harvard theoretical physicist] Lisa Randall, experimenters and theorists used to work in tandem … and now the theorists have moved so far from observations that it’s a little frightening. There’s a need for new instrumentation, the new James Webb telescopes, the new particle accelerators.”

    Which ultimately brings Bartusiak to another part of science that definitely has precedent: the need for funding to support research.

    “The bigger the instrument, the further out you can see, or the further down into spacetime you can see, so I want people to realize that if you want these stories to continue, you’re going to need a further investment,” Bartusiak says. “But that’s what makes us a civilization. That we can take at least some of our wealth and use it to expand our knowledge about where we live. And that includes the universe, not just the Earth.”

    [Strange, no citation of Vera Rubin,

    Vera Rubin measuring spectra (Emilio Segre Visual Archives AIP SPL)

    Astronomer Vera Rubin at the Lowell Observatory in 1965. (The Carnegie Institution for Science)

    Fritz Zwicky,

    Fritz Zwicky, the Father of Dark Matter research.No image credit after long search

    or Dame Susan Jocelyn Bell Burnell

    Susan Jocelyn Bell [maiden name], discovered pulsars with radio astronomy

    Dame Susan Jocelyn Bell Burnell 2009

    I hope they made it into the book.

    See the full article here .

    Please help promote STEM in your local schools.

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    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

    MIT Campus

  • richardmitnick 7:30 am on September 18, 2018 Permalink | Reply
    Tags: 3Q: Sheila Widnall on sexual harassment in STEM, MIT,   

    From MIT News: “3Q: Sheila Widnall on sexual harassment in STEM” 

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    From MIT News

    September 17, 2018
    David L. Chandler

    Sheila Widnall, MIT Institute Professor and former secretary of the U.S. Air Force. Image: Len Rubenstein

    National Academies report cites need for strong leadership and cultural change; will be focus of upcoming MIT panel discussion.

    Sheila Widnall, MIT Institute Professor and former secretary of the U.S. Air Force, was co-chair of a report commissioned by the National Academies of Sciences, Engineering, and Medicine to explore the impact of sexual harassment of women in those fields. Along with co-chair Paula Johnson, president of Wellesley College, Widnall and dozens of panel members and researchers spent two years collecting and analyzing data for the report, which was released over the summer. On Sept. 18, Widnall, Johnson, and Brandeis University Professor Anita Hill will offer their thoughts on the report’s findings and recommendations, in a discussion at MIT’s Huntington Hall, Room 10-250. Widnall spoke with MIT News about some of the report’s key takeaways.

    Q: As a woman who has been working in academia for many years, did you find anything in the results of this report that surprised you, anything that was unexpected?

    A: Well, not unexpected, but the National Academy reports have to be based on data, and so our committee was composed of scientists, engineers, and social scientists, who have somewhat different ways of looking at problems. One of the challenges was to bring the committee together to agree on a common result. We couldn’t just make up things; we had to get data. So, we had some fundamental data from various universities that were taken by a recognized survey platform, and that was the foundation of our data.

    We had data for thousands and thousands of faculty and students. We did not look at student-on-student behavior, which we felt was not really part of our charge. We were looking at the structure of academic institutions and the environment that’s created in the university. We also looked at the relationship between faculty, who hold considerable authority over the climate, and the futures of students, which can be influenced by faculty through activities such as thesis advising, and letter writing, and helping people find the next rung in their career.

    At the end of the report, after we’d accumulated all this data and our conclusions about it, we said, “OK, what’s the solution?” And the solution is leadership. There is no other way to get started in some of these very difficult climate issues than leadership. Presidents, provosts, deans, department heads, faculty — these are the leaders at a university, and they are essential for dealing with these issues. We can’t make little recommendations to do this or do that. It really boils down to leadership.

    Q: What are some of the specific recommendations or programs that the report committee would like to see adopted?

    A: We found many productive actions taken by universities, including climate surveys, and our committee was particularly pleased with ombudsman programs — having a way that individuals can go to people and discuss issues and get help. I think MIT has been a leader in that; I’m not sure all universities have those. And another recommendation — I hate to use the word training, because faculty hate the word training — but MIT has put in place some things that faculty have to work through in terms of training, mainly to understand the definitions of what these various terms mean, in terms of the legal structure, the climate structure. The bottom line is you want to create a civil and welcoming climate where people feel free to express any concerns that they have.

    One of the things we did, since we were data-driven, was that we tried to collect examples of processes and programs that have been put in place by other societies, and put them forward as examples.

    We found various professional societies that are very aware of things that can happen offsite, so they have instituted special policies or even procedures for making sure that a meeting is a safe and welcoming environment for people who come across the country to go to a professional meeting. There are several examples of that in the report, of societies that have really stepped forward and put in place procedures and principles about “this is how you should behave at a meeting.” So I think that’s very welcome.

    Q: One of the interesting findings of the report was that gender harassment — stereotyping what people can or can’t do based on their gender — was especially pervasive. What are some of the impacts of that kind of behavior?

    A: A hostile work environment is caused by the uncivility of the climate. All the little microinsults, things like telling women they can’t solder or that women don’t belong in science or engineering. I think that’s really an important point in our report. Gender discrimination is most pervasive, and many people don’t think it’s wrong; they just don’t give it a second thought.

    If you have a climate where people feel that they can get away with that kind of behavior, then it’s more likely to happen. If you have an environment where people are expected to be polite — is that an old-fashioned word? — or civil, people act respectfully.

    It’s pretty clear that physical assault is unacceptable. So we didn’t deal a lot with that issue. It’s certainly a very serious kind of harassment. But we did try to focus on this less obvious form and the responsibilities of universities to create a safe and welcoming climate. I think MIT does a really good job of that.

    I think the numbers have helped to improve the climate. You know, when I came to MIT women were 1 percent of the undergraduate student body. Now it’s 46 percent, so clearly, times have changed.

    When I came here as a freshman, my freshman advisor said, “What are you doing here?” That wasn’t exactly welcoming. He looked at me as if I didn’t belong here. And I don’t think that’s the case anymore, not with such a high percentage of undergraduates being women. I think increasingly, people do feel that women are an inherent part of the field of engineering, in the field of science, in medicine.

    See the full article here .

    Please help promote STEM in your local schools.

    Stem Education Coalition

    MIT Seal

    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

    MIT Campus

  • richardmitnick 10:29 am on September 7, 2018 Permalink | Reply
    Tags: AIM-Adaptable Interpretable Machine Learning, , Black-box models, , , MIT,   

    From MIT News: “Taking machine thinking out of the black box” 

    MIT News
    MIT Widget

    From MIT News

    September 5, 2018
    Anne McGovern | Lincoln Laboratory

    Members of a team developing Adaptable Interpretable Machine Learning at Lincoln Laboratory are: (l-r) Melva James, Stephanie Carnell, Jonathan Su, and Neela Kaushik. Photo: Glen Cooper.

    Adaptable Interpretable Machine Learning project is redesigning machine learning models so humans can understand what computers are thinking.

    Software applications provide people with many kinds of automated decisions, such as identifying what an individual’s credit risk is, informing a recruiter of which job candidate to hire, or determining whether someone is a threat to the public. In recent years, news headlines have warned of a future in which machines operate in the background of society, deciding the course of human lives while using untrustworthy logic.

    Part of this fear is derived from the obscure way in which many machine learning models operate. Known as black-box models, they are defined as systems in which the journey from input to output is next to impossible for even their developers to comprehend.

    “As machine learning becomes ubiquitous and is used for applications with more serious consequences, there’s a need for people to understand how it’s making predictions so they’ll trust it when it’s doing more than serving up an advertisement,” says Jonathan Su, a member of the technical staff in MIT Lincoln Laboratory’s Informatics and Decision Support Group.

    Currently, researchers either use post hoc techniques or an interpretable model such as a decision tree to explain how a black-box model reaches its conclusion. With post hoc techniques, researchers observe an algorithm’s inputs and outputs and then try to construct an approximate explanation for what happened inside the black box. The issue with this method is that researchers can only guess at the inner workings, and the explanations can often be wrong. Decision trees, which map choices and their potential consequences in a tree-like construction, work nicely for categorical data whose features are meaningful, but these trees are not interpretable in important domains, such as computer vision and other complex data problems.

    Su leads a team at the laboratory that is collaborating with Professor Cynthia Rudin at Duke University, along with Duke students Chaofan Chen, Oscar Li, and Alina Barnett, to research methods for replacing black-box models with prediction methods that are more transparent. Their project, called Adaptable Interpretable Machine Learning (AIM), focuses on two approaches: interpretable neural networks as well as adaptable and interpretable Bayesian rule lists (BRLs).

    A neural network is a computing system composed of many interconnected processing elements. These networks are typically used for image analysis and object recognition. For instance, an algorithm can be taught to recognize whether a photograph includes a dog by first being shown photos of dogs. Researchers say the problem with these neural networks is that their functions are nonlinear and recursive, as well as complicated and confusing to humans, and the end result is that it is difficult to pinpoint what exactly the network has defined as “dogness” within the photos and what led it to that conclusion.

    To address this problem, the team is developing what it calls “prototype neural networks.” These are different from traditional neural networks in that they naturally encode explanations for each of their predictions by creating prototypes, which are particularly representative parts of an input image. These networks make their predictions based on the similarity of parts of the input image to each prototype.

    As an example, if a network is tasked with identifying whether an image is a dog, cat, or horse, it would compare parts of the image to prototypes of important parts of each animal and use this information to make a prediction. A paper on this work: “This looks like that: deep learning for interpretable image recognition,” was recently featured in an episode of the “Data Science at Home” podcast. A previous paper, “Deep Learning for Case-Based Reasoning through Prototypes: A Neural Network that Explains Its Predictions,” used entire images as prototypes, rather than parts.

    The other area the research team is investigating is BRLs, which are less-complicated, one-sided decision trees that are suitable for tabular data and often as accurate as other models. BRLs are made of a sequence of conditional statements that naturally form an interpretable model. For example, if blood pressure is high, then risk of heart disease is high. Su and colleagues are using properties of BRLs to enable users to indicate which features are important for a prediction. They are also developing interactive BRLs, which can be adapted immediately when new data arrive rather than recalibrated from scratch on an ever-growing dataset.

    Stephanie Carnell, a graduate student from the University of Florida and a summer intern in the Informatics and Decision Support Group, is applying the interactive BRLs from the AIM program to a project to help medical students become better at interviewing and diagnosing patients. Currently, medical students practice these skills by interviewing virtual patients and receiving a score on how much important diagnostic information they were able to uncover. But the score does not include an explanation of what, precisely, in the interview the students did to achieve their score. The AIM project hopes to change this.

    “I can imagine that most medical students are pretty frustrated to receive a prediction regarding success without some concrete reason why,” Carnell says. “The rule lists generated by AIM should be an ideal method for giving the students data-driven, understandable feedback.”

    The AIM program is part of ongoing research at the laboratory in human-systems engineering — or the practice of designing systems that are more compatible with how people think and function, such as understandable, rather than obscure, algorithms.

    “The laboratory has the opportunity to be a global leader in bringing humans and technology together,” says Hayley Reynolds, assistant leader of the Informatics and Decision Support Group. “We’re on the cusp of huge advancements.”

    Melva James is another technical staff member in the Informatics and Decision Support Group involved in the AIM project. “We at the laboratory have developed Python implementations of both BRL and interactive BRLs,” she says. “[We] are concurrently testing the output of the BRL and interactive BRL implementations on different operating systems and hardware platforms to establish portability and reproducibility. We are also identifying additional practical applications of these algorithms.”

    Su explains: “We’re hoping to build a new strategic capability for the laboratory — machine learning algorithms that people trust because they understand them.”

    See the full article here .

    Please help promote STEM in your local schools.

    Stem Education Coalition

    MIT Seal

    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

    MIT Campus

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